If all you want to do is point your client to the propery "live" server
at runtime, the all you need to use is the URL property of the proxy
class to programatically change point to the live server.

Example

Public Sub Example()

  Dim newUrl as string
  newUrl = GetServer()

  Dim webProxy as new localhost.webservice 'replace this with you
actual proxy declaration
  webProxy.Url = newUrl

  webProxy.MyWebMethod() 'replace this with the call to your actual
web method.
End Sub

You don't need to worry about changing the WSDL.

I'd also suggest that you look at setting up a UDDI server. A UDDI
server would give you the proper tools to manage the locations of you
services. With UDDI you can upload a copy of your WSDL. All clients
that want to consume your service can retrieve this WSDL from the UDDI
server and can develop against it.  Then, you can configure an access
point in the UDDI service that points to the current live location of
the service that matches your WSDL. The client applications can query
the UDDI server for this access point and can use the code I outlined
above to dynamically point to the live service.As an administrator, you
just need to change the access point in the UDDI server to redirect all
clients to the new location.

Hope that helps.

Peter Kelcey